1. Field of the Invention
This invention relates to a lug tire for agricultural machines.
2. Description of the Prior Art
A tire for agricultural machines serves to effect a traction operation on off-road conditions contrary to a tire for passenger cars or trucks and buses which run on improved roads. As a result, a tire mounted on a driving wheel of the agricultural machine is provided with bar-shaped lugs each projected from a tread center portion to a tread end portion and spaced apart from each other in the circumferential direction of the tire by a transverse groove. In addition, the tire for agricultural machines is of a so-called high lug tire whose lug has a height which is considerably higher than that of the tire for trucks and buses.
In such kind of conventional lug tire, the shape of the outer surface of the lug as a whole is substantially circular or flat in section. The use of the lug having the above mentioned shape results in an increase of the ground contact pressure subjected not only to the tread center portion of the lug but also to the tread end portions of the lug when the tire runs. Hence it provides the disadvantage that the vibrations of the tire produced when it runs become large, the handling becomes deviated and heavy, and the carcass cord tends to be broken at the root position of the lug.